Burma's isolationist regime finally gave clearance on Thursday for the first major international airlift of food for survivors of a devastating cyclone after delays that frustrated aid agencies, but US flights remained grounded due to lack of access, officials said. With a death toll that could eventually exceed 100,000, according to a top US diplomat, Burma's generals were still stalling on visas for UN teams urgently seeking entry to ensure aid is delivered to the victims. UN officials said two of four airplanes arrived in Rangoon while two others would follow, loaded with high-energy biscuits, medicine, and other supplies. The planes had waited for two days while the world body negotiated with the military regime to allow the material in. Eric John, the US ambassador to Thailand, told reporters that US and Thai authorities earlier believed they had permission from Burma to land US military C-130 transport planes. But Burma officials later made it clear this was not the case. Mr John said it was not clear if they had reversed an earlier decision or if there was a misunderstanding. Thailand Prime Minister Samak Sundaravej offered to negotiate on Washington's behalf to persuade the junta to accept US aid. "It is imperative at this point that they do open up and allow a major international relief effort to get under way," said Richard Horsey, who coordinates UN humanitarian aid out of Bangkok. Burma's state media said Cyclone Nargis, which slammed into the Southeast Asian nation on Saturday, killed at least 22,980 people and left 42,119 missing, mostly in the Irrawaddy delta. But a top US diplomat said on Wednesday the toll could go up to more than 100,000. About 5,000 square kilometres of Burma's cyclonehit regions remain underwater, with more than a million people in need of emergency relief, a UN spokesman said on Thursday. "We're talking about 5,000 square kilometres under water," said Richard Horsey. Entire villages in the delta were still submerged, and bloated corpses could be seen stuck in the mangroves. Some survivors stripped clothes off the dead. People wailed as they described the horror of the torrent swept ashore by the cyclone. The UN World Health Organisation has received reports of malaria outbreaks in the worst-affected area, and fears of waterborne illnesses surfacing due to dirty water and poor sanitation also remained a concern, said Poonam Khetrapal Singh, deputy director of WHO's Southeast Asia office in New Delhi. "Safe water, sanitation, safe food. These are things that we feel are priorities at the moment," she said. Burma's generals, traditionally paranoid about foreign influence, issued an appeal for international assistance after the storm struck. They have since dragged their feet on issuing visas to relief workers even as survivors faced hunger, disease and flooding. Even near Rangoon, stricken villagers complained that they had received no government assistance and were relying on Buddhist monasteries, which have been helping the public cope with the disaster. "The government is not helping us. No aid is coming. There is no money, no rice," said Mu Sanda, one of some 50 people huddled in a monastery dining room converted into an evacuation centre in Kyauktan, 25 km southeast of Rangoon. Even China, Burma's closest ally, urged the military junta to work with the international community. Foreign ministry spokesman Qin Gang said China would give 30 million yuan (US$4.3 million) in aid in addition to an initial US$1 million.